This invention relates to improvements in an internal combustion engine with an engine unit support comprising parts directly affected by body resonance as, e.g., cylinder block, cylinderhead, crankshaft, and crankshaft bearings. The engine unit support is connected to a crankcase by means of several vibration absorbing and power transmitting elements whereby the crankcase is insulated against body resonance, and a sealing element is arranged between the engine unit support for the crankcase and sealing a lower oil-wetted part of the engine oil-tightly against an upper dry part.